The two biggest questions going into this almond season are how large will the crop be and how high will the prices soar.

Growers hope the answer to both questions will be the same: “Records.” And chances that could turn out to be right answer.

There may be better years ahead, but none have been more promising so far than 2005 for the grower willing to spend the money to maximize yields.

“The two biggest factors that influence production are nutrition and water,” says Steve Renna, a pest control adviser (PCA) with Western Farm Service in Madera, Calif. Pesticides, fungicides and herbicides are essential, of course, but they can only protect “what's out there,” he says. To produce the highest possible yields, growers must first look to their nutritional programs and water management.

The Potash and Phosphate Institute reports that a ton of almonds removes 130 pounds of N, 50 pounds of P, and an astounding 170 pounds of K from the soil. Adding only these amounts in a nutritional program will reduce future harvests as uptake inefficiency requires extra fertilizer to be applied beyond plant uptake.

“Potassium is definitely a limiting factor in almonds,” Renna points out. “While nitrogen contributes to tree growth, potassium goes straight to the nuts and developing fruiting wood. “I think growers often use too much N and not enough potassium and micronutrients.”

Awareness of the need for potassium is low, according to the PCA, who services about 10,000 acres of almonds in Madera and northern Fresno counties. In recent years UC Davis researchers have been recommending increasing amounts of potassium in foliar applications.

Frequent sampling

In order to establish a nutrition program, Renna recommends frequent and regular soil and tissue sampling. “At Western Farm Service, we have 20 years of data showing average nutrient content of leaves from full leaf expansion through harvest — not just in July,” he says. “By taking tissue tests early, there is still time to make corrections in the foliar nutrient program.”

“We try to get N-P-K into the tree after harvest while the soil is still warm,” he says. In the winter, under cold, wet conditions, nutrient uptake is poor, which is why he also recommends an in-season soil N-P-K application in March, except under micro-sprinklers, which require frequent, smaller-dose applications. From there on, he recommends foliar testing and monthly nutrient sprays during the growing season.

“It's important to have plenty of nutrients in the trees in anticipation of when the tree demands it most,” he says. “For instance, at bloom and just prior to nut fill is when trees have the highest demand for potassium. The potassium must be in place before the demand.”

Calcium and boron are two other nutrients essential to maximum nut production. “Timing is critical for nutrient applications, whether soil-or foliar-applied,” Renna says. “Calcium in early bloom sprays prevents premature shed, and boron contributes to pollen viability. Growers may miss the boat by not putting on calcium and boron early because levels of these nutrients decline in the plant as the year progresses,” he says, adding that tissue tests should be used to determine the requirements.

Balanced application

A balanced calcium-boron foliar nutrient should be used, such as Western Farm Service's formulation called First Choice Cal Max for Trees & Vines. Renna recommends adding AuxiGro to the tank to maximize nutrient uptake. “AuxiGro, a nutritional manager or gatekeeper, gets the calcium into the plant and throughout the tree,” he says. “We recommend three applications of AuxiGro at the labeled rate of 4 ounces per acre along with Cal Max at pink bud, full bloom, and petal fall.” Applications should be at least seven days apart.

AuxiGro enhances nutrient utilization by opening up plant cells to allow calcium and boron to move across the cell membrane, according to Jerome Pier, agronomist for the Central Valley Division of Western Farm Service in Stockton.

“In a healthy tree, AuxiGro ‘tricks’ the plant into a stress response, although no stress may be occurring, resulting in a higher state of metabolism,” he explains.

This activity is especially important during bloom time because the trees need to mobilize nutrients to provide for breaking dormancy and to relieve stress from poor weather conditions. At this time, according to the agronomist, the trees must rely on nutrients stored in the scaffold and wood because there are no leaves to supply nutrients. “Whatever is already in the tree is what the tree has to work with,” Pier points out.

This early time frame is also critical for setting the crop. “Setting the crop is the first step toward a maximum harvest,” Pier says. “It's a long time from bloom to harvest and lots of things can go right — or wrong. By supplying trees with sufficient nutrients for the extra yield potential, and using AuxiGro to increase uptake of these nutrients, more nuts can be carried all the way through to harvest.

More nuts

“In trials with AuxiGro,” he reports, “we have seen not bigger almonds, just more nuts for overall higher yields by at least 100 pounds to the acre. This includes all our data from earliest use of AuxiGro experimentally. In three years of commercial use, we've been 90 percent successful in satisfying our customers.”

“In the long run,” Renna says, “using AuxiGro to increase nutrient utilization relieves stress and improves the health of the tree. I'm in the process of tracking yields over multiple years and correlating this with the nutritional status of the tree so we know what our fertility goals should be.”

Moisture, the other factor Renna points out is essential for maximum production, must also be supplied early in the season so it is available to the tree in anticipation of need.

“Pay attention to moisture in the soil profile,” he warns. “We're getting above normal rain this winter so the soil profile probably won't have a deficit, but if the rains don't continue and the soil profile is empty, double-line drip or micros can't keep up with the evapotranspiration of trees,” he explains. “Growers need to start the water early so the soil is not dry when the trees start to need moisture. And during the season, don't go too far between water applications, which can stress the trees. Going four to five days between applications in the summer can affect next year's crop. Trees that defoliate early because they lack moisture won't put on as good a crop the following year.

“If the plant is not stressed from lack of water and nutrients, and from pest damage, you'll produce maximum yields,” Renna concludes.

Misperception

Agronomist Pier agrees, saying that “In our trials with AuxiGro, we had very good success where the trees have had sufficient moisture and nutrients supplied in advance of need. There's a misperception that in trials, plots with AuxiGro should be managed the same as controls in terms of water and nutrient management. Where we are able to stimulate metabolism with AuxiGro and set more nuts, the trees will need more moisture and more nutrients to feed the heavier crop. AuxiGro can stimulate a good tree to produce better, but it won't make up for lack of resources.”

“This is the year to maximize yields,” agrees Stan Darnell, a PCA with Mid Valley Ag in Hughson, Calif. In his area, three of the more important tools to accomplish this are to correct soil condition, increase fertilizer, and add AuxiGro to maximize nutrient uptake.

“Growers have been neglecting to correct soil pH in this area,” he says. “It takes multiple applications of lime, which is costly. Now that growers have a little money in their pockets, this is a good time to upgrade their production.”

Growers also need to increase levels of potassium, which is another expensive input, costing $100 per acre, according to the PCA. “Almonds need and use a lot of potassium,” he says, adding that while some growers apply it religiously on an annual basis, others tend to cut back.

“I would estimate that growers are increasing their inputs by 25 percent up to 30 percent this year,” Darnell says.

“We've learned from company research and our own trials with growers that they get good results increasing yield with AuxiGro by a minimum of 100 pounds per acre and often more. This year they will be spending $50 an acre for AuxiGro to get at least $250 an acre in return; in some instances the yield increases have been even more dramatic.”

In his program, AuxiGro is applied as a piggyback with fungicides and a nutrient spray at pink bud, full bloom, and petal fall, or at least 10 days apart. “Growers don't always make a third application of fungicide,” he says, “but some make a third application of AuxiGro with just the nutrient spray, using a calcium complex called Carbo-Cal from RNA, along with a nutrient package custom made to fit local needs. It also buffers the pH when used with AuxiGro to between 6 and 7, depending on the starting pH.” In the tank, the pH has to be kept between 6 and 7 when applying AuxiGro, he explains, adding that you must use a silicone surfactant, which is essential for uptake and spreading. Oil may not be used with AuxiGro.

Price not factor

Chowchilla, Calif., grower David Talley also names soil condition, fertility, and moisture management as keys to maximum production. “My philosophy is to grow the biggest crop I can, whether prices are high or low,” he says. “I never vary inputs on the basis of the price of the crop,” he adds. “Whatever you put into the crop is an investment — some of it goes for this year's crop, but some also is an investment in next year's crop and beyond. I'm interested in the long-term health of the tree.”

To condition the fine sandy loam soil prevailing on his 400 acres of almonds, each year Talley applies 2 tons per acre of gypsum and 500 pounds per acre of potassium sulfate, as well as compost and shredded prunings “to open up the soil and to hold moisture,” he says. “There is a strong correlation between soils with high water penetration rates and our better producing orchards,” he says. “This is because the trees need adequate water penetration to utilize fertilizer.”

Talley begins his moisture management program with a deep watering at mid-winter. “After harvest is one of the most critical time for moisture,” he says. “If we've had a hot harvest, trees can get stressed and drop leaves.”

Talley makes a “big push” in the spring to get good growth, according to his crop consultant, Chris Morgner, Agri-Valley Consulting, Merced, Calif. “He starts early with irrigation because it is tough to get water deep into the soil profile,” Morgner says. “It's important to have a full profile at the beginning of the season so there are no sharp spikes in soil moisture during the season. Once the trees are leafed out, we can get water down to only about 18 inches or so, using flood irrigation.”

New planting needs

Talley is careful to manage irrigation on new plantings “to be sure to fill the soil profile down to five feet. If the ground hasn't been used for a couple of years, the soil will have dried out,” he says.

Morgner samples soil on Talley's ground every three to five years; sooner only if a problem is suspected or satellite imagery shows there is a problem area. Leaf sampling is done throughout the season, and Morgner recommends choosing one variety and sampling only that variety in the same area each time. “This helps to establish a pattern from year to year,” he says.

“Staying on top of the nutrient demands of the tree benefits the next year's crop as well as the current one. Bud formation for next year's crop starts in July and the crop is determined by September,” he says.

Talley's foliar nutrients include Solubor and calcium at pink bud, and zinc is added at petal fall in May. To enhance nutrient uptake, AuxiGro is added to fungicide spray timed for pink bud; the next application is targeted for 10 days later. “Depending on the weather, we may stretch this out more,” says consultant Morgner. “And we'll put on three applications, according to the label; the third one will go out even if we don't need the fungicide.” This season, the consultant says, he recommends adding urea to the tank because urea enhances leaf uptake of nutrients, and possibly of AuxiGro.

“I don't get into a lot of new products, especially unproven ones,” Talley says, “but I'm confident in AuxiGro because it has dual registration as a yield enhancer and as a tool against fungal diseases, especially in a drier year. Last year, for instance, I even used AuxiGro in place of one of my fungicide sprays. The data I've seen on AuxiGro is convincing, but the bottom line for me is I got more nuts.”

Talley has been treating all his bearing trees with the same TLC — including trees in their first year of harvest. “With the prices so good, I'm doing everything I can to boost production. Even on three-year-old trees I try to maximize yield, and just turn down the pressure on the shaker so we don't hit them as hard,” he says.

Talley also produces and sells 150,000 almond trees per year as Talley Nursery LLC. “I started the nursery because I wanted to manage my trees for their entire life,” he says. “Growing almonds is like reading a good book; you don't ever want it to end.”